Stackable interlocking intervertebral support system

ABSTRACT

An intervertebral support system, comprising: a center portion having top and bottom recesses; a top portion having a bottom recess, the bottom recess in the top portion interlocking with the top recess in the center portion when the top position is positioned on top of the center portion; and a bottom portion having a top recess, the top recess in the bottom position interlocking with the bottom recess in the center portion when the bottom portion is positioned under the center portion.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a divisional of commonly owned and co-pendingU.S. patent application Ser. No. 09/904,179 filed Jul. 11, 2001, thecomplete disclosure of which is hereby incorporated herein by referencein its entirety for all purposes. Additionally, the present applicationclaims benefit under 35 U.S.C. § 119(e) from U.S. ProvisionalApplication Ser. No. 60/218,975, filed on Jul. 17, 2000, the entirecontents of which are hereby expressly incorporated by reference intothis disclosure as if set forth fully herein.

BACKGROUND OF THE INVENTION

The present invention provides a stackable interlocking intervertebralsupport system, and methods for supporting adjacent vertebrae using astackable interlocking intervertebral support system.

SUMMARY OF THE INVENTION

In preferred aspects, the present system comprises two, three (or more)separate portions which are stacked together to form an interlockedintervertebral support assembly. Advantageously, two of these three (ormore) portions may be identical in size and shape, as will be explained.In the optional aspect of the invention in which only two separateportions are used, these two portions may be identical to one another insize and shape.

In one preferred aspect, the present invention preferably comprises acenter portion, a top portion and a bottom portion. The top portion ispositioned on top of the center portion and the bottom portion ispositioned under the center portion. The top and bottom portions may beidentically shaped and dimensioned, but are positioned upside down withrespect to one another, on opposite sides of the center portion, as willbe explained. In another aspect of the invention, however, only twoportions are used, with the top portion being positioned directly on topof the bottom portion (with no center portion(s) required). In furtheraspects of the present invention, more than three separate portions maybe used. In such aspects, a plurality of identically shaped centerportions are stacked one on top of the other. In other alternateaspects, various portions (including top, center and bottom portions)may be stacked side by side one another).

In accordance with the present invention, the center portion has arecess in each of its top and bottom surfaces. Each of the top andbottom portions of the present system also have recesses therein whichengage and interlock with the recesses in the center portion. Morespecifically, the top portion preferably has a recess in its bottomsurface and the bottom portion has a recess in its top surface whichengage the respective recesses in the top and bottom of the centerportion.

The present invention is assembled simply by stacking the three portions(top, center & bottom) one on top of one another in a patient'sintervertebral space. When stacked together, the present assembly willform an “X” or “cross” type of shape, providing support over a largesurface area of the adjacent vertebrae. In further optional aspects ofthe invention, more than three portions are stacked together one on topof one another in a patient's intervertebral space. Specifically, aplurality of center portions are stacked on a bottom portion and a topportion is stacked thereover.

A further advantage of the present system is that, when assembled, itprovides support in two perpendicular directions, thereby supporting alarge area of the adjacent vertebrae, yet using only a minimal amount ofmaterial in actually achieving this advantage. This advantage is due, atleast in part, to the assembled “cross” shape of the assembly. Moreover,the present invention can be dimensioned to be of a size such that the“arms” of the “cross” extend outwardly towards the edges of thevertebrae, providing support over the cortical bone at the vertebraledges.

Another advantage of the present invention is that, as the adjacentvertebrae tend to push together, this will hold the present supportassembly together, even in the absence of any mechanical fastening orsecuring mechanisms between the top, center & bottom portions of thesystem. Specifically, both (one or more) center portion(s) and the twotop/bottom portions are uniquely shaped and dimensioned such that whenpositioned one on top of another, they will remain firmly together,resisting any lateral tendency to slip apart.

Yet another advantage of the present invention is that it may be easilyinserted into a patient's intervertebral space in a bi-portal minimallyinvasive surgical approach. Specifically, the bottom portion may beinserted through a first cannula into the patient's intervertebralspace, with the center portion(s) thereafter being inserted through asecond cannula into the patient's intervertebral space. The top portionmay then be inserted through the first cannula into the patient'sintervertebral space. In this aspect of the invention, the first andsecond cannulae are generally perpendicular to one another, beingpositioned in opposite posterolateral approaches. Alternatively, all ofthe portions of the assembly may be inserted through the same operatingcannula into the patient's intervertebral space, with successiveportions then rotated perpendicular to one another after they have beenpositioned in the patient's intervertebral space.

In preferred aspects, each of the center, top and bottom portions of theassembly have a tapered end, which is dimensioned to engage a rampingstructure disposed within one of the recesses on an adjacent portionsuch that the separate portions of the assembly may be “slip-fit”together, with pressure between the adjacent vertebrae holding each ofthe pieces of the assembly together. In addition, an optional taperedfront end of the center portion may be used to pry apart the adjacentvertebrae, prior to positioning the top portion thereover.

In optional aspects of the invention, a plurality of the present supportassemblies can be positioned in a patient's intervertebral space, eitheron top of, beside, or both on top of and beside, one another.

BRIEF DESCRIPTION OF THE DRAWINGS

Many advantages of the present invention will be apparent to thoseskilled in the art with a reading of this specification in conjunctionwith the attached drawings, wherein like reference numerals are appliedto like elements and wherein:

FIG. 1 is an exploded front/side perspective view of an exemplaryarrangement of the present stackable interlocking intervertebral supportsystem;

FIG. 2 is a top front/side perspective view of the exemplary arrangementof the present system seen in FIG. 1;

FIG. 3 is a bottom front/side perspective view of the exemplaryarrangement of the present system seen in FIG. 1;

FIG. 4 is a top plan view of the exemplary arrangement of the presentsystem seen in FIG. 1;

FIG. 5 is a front/side elevation view of the exemplary arrangement ofthe present system seen in FIG. 1, (shown in two adjacent vertebrae inan exploded view);

FIG. 6 is a rear elevation view of the exemplary arrangement of thepresent system seen in FIG. 1;

FIGS. 7A, 7B and 7C are front perspective views of the center portion ofthe present system;

FIG. 8 is a rear perspective view of the center portion of the presentsystem;

FIG. 9A is a top plan view of the center portion of the present system;

FIG. 9B corresponds to FIG. 9A, but has center ramp/recesses angled to alateral axis across the center portion;

FIG. 10 is a side elevation view of the center portion of the presentsystem;

FIG. 11 is a front elevation view of the center portion of the presentsystem;

FIG. 12 is a top front perspective view of the bottom portion of thepresent system, (or is a bottom perspective view of the top portion ofthe present system);

FIG. 13 is a top rear perspective view of the bottom portion of thepresent system, (or is a bottom perspective view of the top portion ofthe present system);

FIG. 14 is a bottom rear perspective view of the bottom portion of thepresent system;

FIG. 15 is a top plan view of a bottom portion of the present system;

FIG. 16 is a side elevation view of the bottom portion of the presentinvention;

FIG. 17 is a front elevation view of the bottom portion of the presentinvention;

FIG. 18 is a top perspective view of a patient's intervertebral spaceshowing the positioning of the present system (with one vertebra shownin phantom);

FIG. 19 is a top plan view of a patient's intervertebral space showingposterolateral approaches used in positioning the separate portions ofthe present system;

FIG. 20 is an exploded perspective view of a patient's intervertebralspace showing an assembly comprising four portions, (including twocenter portions, a top portion and a bottom portion) positioned one ontop of the other; and

FIG. 21 is an exploded perspective view of a two-portion intervertebralsupport assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure. The stackable interlocking intervertebral supportsystem disclosed herein boasts a variety of inventive features andcomponents that warrant patent protection, both individually and incombination.

Referring first to FIG. 1, an exploded front side perspective view ofthe present stackable interlocking intervertebral support system 5 isprovided. In one preferred arrangement, system 5 comprises a centerportion 10, a bottom portion 20A and a top portion 20B. (As will beexplained, other arrangements are possible). As can be seen throughoutthe attached Figs., portions 20A and 20B may preferably be identical inshape and size. Accordingly, the present system 5 may actually compriseone center portion 10 and two top/bottom portions 20.

FIGS. 2 and 3 show respective top and bottom perspective views of thepresent system, in an assembled format. As will be explained, anadvantage of the present system is that it provides support betweenadjacent vertebrae without requiring any mechanical fastening systemsbetween the top, center and bottom portions of the assembly. Rather,center portion 10, bottom portion 20A and top portion 20B are allassembled together with their novel shapes assisting in keeping themtogether.

Referring to the attached Figs., (and to FIGS. 7A to 10 in particular),center portion 10 is provided with bottom recess 11A and top recess 11B,passing thereacross, as shown. Also referring to the attached Figs.,(and to FIGS. 13 to 16 in particular), bottom portion 20A is also provedwith a top recess 21A. (Conversely, being identically shaped to bottomportion 20A, top portion 20B is also provided with a bottom recess 21B).

An important aspect of the present invention is that, when bottomportion 20A is positioned below center portion 10, recess 21A willengage and interlock with recess 11A. Conversely, when top portion 20Bis positioned on top of center portion 10, recess 21B will engage andinterlock with recess 11B. Accordingly, when center portion 10, bottomportion 20A and top portion 20B are stacked together, recesses 11 willengage recesses 21, such that assembly 5 forms an “X” or “cross” shape.As can be seen, recesses 11 and 21 are preferably positioned mid-way(ie: centrally) along the respective lengths of portions 10 and 20. Asillustrated, assembly 5 will have an “X” shape with each of the fourbranches of the “X” being relatively equal in length. Within the scopeof the present invention, however, recesses 11 and 21 may instead bepositioned closer to one end of their respective portions than another,such that the “X” shape of the present assembly will instead have two ofits branches longer than another two of its branches (and may evenapproach a “V” shape assembly). Moreover, the angles at which recesses11 and 21 cut laterally across portions 10 and 20 can be angled asdenoted by angle “α” in FIG. 9B (for center portion 10). As such, whenstacked together, the angles between each of the 4 “arms” of the “X” ofthe present assembly need not be perpendicular to one another. (Forexample, 2 pairs of arms may be 60° apart, with the other 2 pairs ofarms being 120° apart).

As can be seen throughout the attached Figs., center portion 10 has abottom surface 12 and a top surface 14. Bottom portion 20A has a bottomsurface 22A, and top portion 20B has a top surface 22B. When the threeportions of the present assembly are assembled, surface 14 is coplanarwith surface 22B and surface 12 is coplanar with surface 22A. As shownin FIG. 5, surfaces 12 and 22A together support (ie: buttress against)vertebra 50 and surfaces 14 and 22B together support (ie: buttressagainst) an opposite adjacent vertebra 52. (For illustration purposesonly, opposite adjacent vertebrae 50 and 52 are shown in an explodedview). It is to be understood that after distraction vertebrae 50 and 52will tend to move toward one another, applying pressure to the top andbottom of assembly 5, keeping assembly 5 together. As can be seen,surfaces 12, 14, 22A, and 22B may all have a plurality of small groves23 (or other surface irregularities) which increases sliding frictionacross these surfaces.

A further advantage of the novel shape of center portion 10 is that ithas a tapered front end 13. In a preferred method of assembling thepresent support assembly 5, as illustrated in FIGS. 18 and 19, centerportion 10 is advanced minimally invasively into patient P in aposterolateral approach through cannula 60 and positioned betweenopposite adjacent vertebrae 50 and 52 (shown here as being on top ofvertebra 50). Tapered end 13 will tend to pry apart adjacent vertebrae50 and 52, providing the surgeon with a “self-distracting” vertebralsupport system. Bottom portions 20A and top portions 20B are advancedthrough minimally invasive cannula 62 in an opposite posterolateralapproach. Typically, bottom portion 20A is positioned first, followed bycenter portion 10 and top portion 20B stacked sequentially thereover.

Each of center portion 10 and top portion 20B also have tapered frontends 13 and 25 which (as center portion 10 and top portion 20B aresequentially slipped over bottom portion 10 and center portion 10), willengage ramp structures 17 disposed within recesses 21A and 11A inrespective bottom portion 20A and center portion 10, such that centerportion 10 and top portion 20B are “snap-fitted” over bottom portion20A. More specifically, during insertion, vertebrae 50 and 52 will tendto rest against surfaces 12 and 14 of center portion 10. As centerportion (s) 10 and top portion 20B are “snap-fitted” over bottom portion20A and center portion 10, their respective tapered ends 13 and 25 willassist in urging vertebrae 50 and 52 apart. When assembled, rampstructures 27 disposed within recesses 21A and 21B will interlock withengage ramp structures 17 in center portion 10, such that assembly 5will be held together, by intervertebral pressure (on surfaces 14 and22B, and surfaces 12 and 22A) urging vertebrae 50 and 52 together.

Portions 10 and 20 of the present invention may preferably each have anarrow elongated shape, as shown. Accordingly, they may be dimensionedto be small enough to pass through an operating cannula, for example, anoperating cannula having an interior diameter equal to, or less than, 8mm or 6 mm.

In preferred aspects of the invention, portions 10 and 20 are preferablymade of bone allograft material, offering the advantages of promotinghealing and eventual absorption of system 5. Alternatively, portions 10and 20 may be made of metal, or any other suitable bio-implantablematerial. Each of center portion 10, and top/bottom portion 20 mayoptionally have side grooves 15 and 25 in which opposite prongs 42 of atwo prong inserter 40 (such as a “pinching” inserter as shown in FIGS.7A and 13) which may be used when inserting each of center portion 10and top/bottom portions 20 through respective surgical cannulae 60 and62.

If desired, the vertical height of the present system can be increasedby stacking more than one center portion 10 (as shown in FIG. 20 inwhich an assembly 5A is shown having two center portions 10). It is tobe understood that more than two center portions 10 may be used inassembling the present intervertebral support system, as desired. In yetanother optional aspect of the invention, assemblies 5 may be made smallenough such that more than one can be positioned side by side in apatient's intervertebral space. As is seen in FIG. 21, a two portionintervertebral support assembly 5B is also contemplated. In this aspectof the invention, top portion 20B is positioned directly on top ofbottom portion 20A, with recesses 21A and 21B interlocking together.Many other system arrangements are possible. For example, two, or morethan two portions 10 can be stacked on top of one another (similar tothe stacking of portions 20 in FIG. 21).

1. A spinal support system, comprising: a plurality of elongated insertshaving ramped distal portions for successively increasing the height ofa space within a spine.
 2. The spinal support system of claim 1, whereinsaid ramped distal portions are dimensioned to assist in advancing atleast a first of said plurality of elongated inserts into positionadjacent to at least a second of said plurality of elongated inserts. 3.The spinal support system of claim 1, wherein each of said plurality ofelongated inserts is dimensioned to be received through a surgicalcannula.
 4. The spinal support system of claim 1, wherein said pluralityof elongated inserts are composed of bone allograft.
 5. The spinalsupport system of claim 1, wherein each of said plurality of elongatedinserts include a plurality of grooves for engagement with an insertiontool.
 6. A method for increasing the height of a space within a spine,said method comprising the steps of: (a) providing a plurality ofelongated inserts, each elongated insert having a ramped distal portion;and (b) successively advancing said plurality of elongated inserts intosaid space within a spine such that said elongated inserts arepositioned vertically adjacent one another.
 7. The method of claim 6,wherein said plurality of elongated inserts are advanced into a spacewithin a spine through a surgical cannula.
 8. The method of claim 6,wherein said plurality of elongated inserts are composed of boneallograft.
 9. The method of claim 6, wherein each of said plurality ofelongated inserts include a plurality of grooves for engagement with aninsertion tool.
 10. The method of claim 6, wherein step (b) comprises:advancing a first elongated insert into a space in a spine; andadvancing second elongated insert into said space such that said rampeddistal portion of said second elongated insert interacts with said firstelongated insert to assist in positioning said second elongated insertvertically adjacent to said first elongated insert.
 11. The method ofclaim 10, wherein step (b) further comprises: advancing at least a thirdelongated insert into said space such that said ramped distal portion ofsaid third elongated insert interacts with said second elongated insertto assist in positioning said third elongated insert vertically adjacentto said second elongated insert.